Figure 2.

(a) An illustration of the vertical-stage microscope with Köhler illumination (side view). “A” is the camera; “B” is a 4× objective lens; “C” is LED illumination. (b) Original trajectories (red) were reduced to the large-scale motility dynamics by a median filter that removes the helical swimming oscillations (blue). (c) Fraction of the cell population that are swimmers is shown. (d) Swimming speed is shown. The solid cirlce, solid triangle, and solid square symbols, respectively, represent a sample size of two, three, and four. Error bars indicate the standard error of the mean. To see this figure in color, go online.